No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.
Interpretation
Scientific theories are provisional and subject to change rather than being seen as absolute truths.
In this quote, Karl Popper emphasizes the idea that scientific theories should not be considered as definitive truths. Instead, they are always open to questioning, revision, and falsification. This notion highlights the dynamic and evolving nature of scientific inquiry, suggesting that the pursuit of knowledge is an ongoing process rather than a conclusion to be firmly established.
In practice
In a science class discussing the nature of scientific theories.
The growth of our knowledge is the result of a process closely resembling what Darwin called 'natural selection'; that is, the natural selection of hypotheses: our knowledge consists, at every moment, of those hypotheses which have shown their (comparative) fitness by surviving so far in their struggle for existence, a competitive struggle which eliminates those hypotheses which are unfit.
If you can't say it simply and clearly, keep quiet, and keep working on it till you can.
The belief in a political Utopia is especially dangerous. This is possibly connected with the fact that the search for a better world, like the investigation of our environment, is (if I am correct) one of the oldest and most important of all the instincts.
A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others - not by simply taking over another's opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others
Thus science must begin with myths, and with the criticism of myths; neither with the collection of observations, nor with the invention of experiments, but with the critical discussion of myths, and of magical techniques and practices.
I am opposed to looking upon logic as a kind of game. ... One might think that it is a matter of choice or convention which logic one adopts. I disagree with this view.
Even if 'going retrograde' or 'moving into Aquarius' were real phenomena, something that planets actually do, what influence could they possibly have on human events? A planet is so far away that its gravitational pull on a new-born baby would be swamped by the gravitational pull of the doctor's paunch.
I do not want to drive across a bridge designed by an engineer who believed the numbers in structural stress models are relative truths.
I thought scientists were going to find out exactly how everything worked, and then make it work better. I fully expected that by the time I was twenty-one, some scientist, maybe my brother, would have taken a color photograph of God Almighty—and sold it to Popular Mechanics magazine. Scientific truth was going to make us so happy and comfortable. What actually happened when I was twenty-one was that we dropped scientific truth on Hiroshima.
My expertise is the space program and what it should be in the future based on my experience of looking at the transitions that we've made between pre-Sputnik days and getting to the moon.
The brain is the most complicated organ in the universe. We have learned a lot about other human organs. We know how the heart pumps and how the kidney does what it does. To a certain degree, we have read the letters of the human genome. But the brain has 100 billion neurons. Each one of those has about 10,000 connections.
Once you can reproduce a phenomenon, you are well on the way to understanding it.
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